3-Inch Trash Pump

3941-96, 3942-D6, 3943-96, 3944-96 & 3946-96
Specifications Information and Repair Parts Manual
Please read and save this Repair Parts Manual. Read this manual and the General Operating Instructions carefully before attempting to assemble, install, operate
or maintain the product described. Protect yourself and others by observing all safety information. The Safety Instructions are contained in the General Operating
Instructions. Failure to comply with the safety instructions accompanying this product could result in personal injury and/or property damage! Retain instructions
for future reference. AMT reserves the right to discontinue any model or change specifications at any time without incurring any obligation.
©2016 AMT Pump Company, A Subsidiary of The Gorman-Rupp Company, All Rights Reserved.
Periodic maintenance and inspection is required on all pumps to ensure proper operation. Unit must be clear of debris and sediment. Inspect for leaks and loose bolts. Failure to do so
voids warranty.
3-Inch Trash Pump
Refer to form 1808-633-00 for General Operating and Safety Instructions.
DESCRIPTION
These trash pumps are high capacity, heavy duty, centrifugal, engine driven, self-priming (to 20 ft. lift) portable units. The pumps are equipped with a precision
lapped mechanical seal to reduce leakage, carrying handle and a clog-resistant impeller capable of handling solids up to 1-1/2” diameter (up to 25% by volume).
A 3” NPT suction strainer is included. Handles liquids from 40º to 180º F (4º to 82º C). For use with nonflammable liquids compatible with pump component
materials.
NOTE: Electric-start models require a 12-volt, 32 amp hour battery (not included).
MAINTENANCE
12. Secure the adapter on the engine mounting face.
NOTE: Tighten cap screws EVENLY to avoid cracking rabbet on engine
mounting face.
13. Apply a light coating of soapy water to the inside rubber portion of seal
cartridge and slide onto the shaft sleeve. Slip the shaft sleeve with seal
cartridge onto the engine shaft.
IMPORTANT: Before installing new shaft sleeve, apply a bead of nonhardening, pliable sealant (such as Permatex® Form-A-Gasket® No. 2) to
motor shaft shoulder.
14. Replace any impeller shim removed in disassembly.
15. Screw the impeller back in place tightening until it is seated against shims
and shaft sleeve.
16. Remount volute with fasteners.
17. Refer to section entitled SHIM ADJUSTMENT at this time if shaft sleeve
or any other parts listed therein have been replaced.
18. Inspect position of flapper valve assembly (Ref. No.15) to ensure proper
movement and seating.
19. Replace o-ring seal on volute rabbet.
NOTE: Always inspect o-ring seals. Replace when cracked or worn. Wet
o-ring with soapy water for ease of assembly.
20. Remount casing.
21. Remount any other parts and reconnect spark plug wire. Pump should
now run with renewed original performance.
To prevent accidental starting, always remove the spark plug or
disconnect and ground the spark plug wire before attempting to service
or remove any component.
CLEANING
These units are designed so that for most cleanout or clogging problems it
should not be necessary to remove hoses or piping. The suction area and
impeller chambers can be reached by removing (2) threaded handles (Ref. No.
22), suction cleanout cover plate (Ref. No. 21) and gasket (Ref. No. 20).
NOTE: When replacing cleanout cover plate, carefully wipe clean all surfaces
on which the gasket has contact. Also, make sure the gasket is in position.
MECHANICAL SEAL REPLACEMENT
Refer to figures 1 and 2.
NOTE: Always replace the seal seat (Ref. No. 8), seal cartridge (Ref. N. 9),
and shaft sleeve (Ref. No. 10) to ensure proper mating of mechanical seal
components!
1. Unthread cap screws (Ref. No. 24) to remove casing (Ref. No. 19) and
casing seal (Ref. No. 7) from adapter (Ref. No. 9).
2. Unthread screws (Ref. No. 13) and remove volute (Ref. No. 14) from
adapter.
3. Unscrew impeller (Ref. No. 12) from the engine shaft. Remove the
impeller shims (Ref. No. 11), shaft sleeve and seal cartridge from engine
shaft. Use a rubber mallet or soft block of wood to loosen impeller. Turn
counterclockwise.
4. Unthread cap screws (Ref. No. 3) and remove the adapter from the engine
mounting face.
5. Push seal seat from the adapter recess with a screwdriver.
6. Clean the adapter recess before inserting a new seal seat.
7. Carefully wipe the polished surface of the new seal seat with a clean cloth.
8. Wet the rubber portion of the seal seat with a light coating of soapy water.
9. Press the new seal seat squarely into the cavity in the adapter. If the seal
seat does not press squarely into the cavity, it can be adjusted in place
by pushing on it with a piece of pipe. Always use a piece of cardboard
between the pipe and the seal seat to avoid scratching the seal seat. (This
is a lapped surface and must be handled very carefully).
10. After the seal seat is in place, ensure that it is clean and has not been
marred.
11. Using a clean cloth, wipe the shaft and make certain that it is perfectly
clean.
3941-252-00
SHIM ADJUSTMENT
1.
2.
3.
4.
1
When installing a replacement impeller, engine, shaft sleeve, adapter or
volute, it may be necessary to vary the number of impeller shims (Ref.
No. 11) that will be required. This is easily done by adding one 0.010”
shim more than was removed and reassembling pump as described in
Mechanical Seal Replacement section.
Ensure that volute (Ref. No. 14) and adapter (Ref. No. 4) are fitted firmly
(check fastener Ref. Nos. 3 & 13). Remove spark plug wire from engine
and turn engine over by pulling the recoil starter. If engine does not run
freely, disassemble pump and remove one shim.
Proper running clearance is 0.010”.
Follow the above procedure until proper clearance is obtained. This will
ensure maximum performance.
6/2016
3941-96, 3942-D6, 3943-96, 3944-96 & 3946-96
Specifications Information and Repair Parts Manual
3-Inch Trash Pump
IMPELLER AND WEARPLATE REPLACEMENT
Impeller (Ref. No. 12), volute/wearplate (Ref. No. 14) and rear wearplate (Ref.
No. 5) are subject to wear only by abrasive sand or sediment laden liquids. If
badly worn, all these parts can be replaced easily and the pump thus restored
to full efficiency.
NOTE: When the clearance between the impeller and the volute/wearplate
exceeds 1/16” at the face of the impeller or 1/8” on the outside diameter of
the impeller, it may be necessary to take corrective action. The increased
clearance can cause lengthened priming and decreased capacity to your
unit. If performance is satisfactory for your application, it is recommended
that no corrective maintenance be performed regardless of what clearances
on your unit may have developed. This is because increased clearances in
themselves are not generally harmful to your pump. Normally, new pump
clearances can be restored by simply shimming behind the impeller. (Add
shim washers Ref. No. 11). If the impeller is badly worn, it is recommended
that the impeller be replaced. This is usually all that is required since only
on abrasive surfaces does the cast iron wearplate show deterioration.
Occasionally a stone or hard object might get caught in the impeller and
cause damage to the volute/cutwater. In these cases follow the instructions
below for replacement and refer to Figure 1.
Figure 1 - Mechanical Seal Replacement
1.
Disassemble pump for access as described in Mechanical Seal
Replacement, steps 1 and 2.
2. Replace parts as necessary.
NOTE: When replacing volute/wearplate, attach flapper valve assembly (Ref.
No. 15) to the new volute with fastener (Ref. No. 16).
3. To replace rear wearplate (Ref. No. 5), remove fasteners (Ref. No. 6)
after impeller has been removed.
NOTE: Before Installing new parts, clean all mating surfaces thoroughly.
SUCTION FLANGE REPLACEMENT
1.
2.
3.
4.
Unthread the four screws on the suction flange (Ref. No. 28).
Remove the old gasket.
Replace the gasket. Gasket must be installed between suction flange
and casing for proper seal and priming.
Install new suction flange and thread the four bolts to the casing. Tighten
the bolts in an alternating pattern to avoid pinching
DISCHARGE FLANGE REPLACEMENT
1.
2.
3.
4.
Unthread the four screws on the discharge flange (Ref. No. 17).
Remove the old gasket.
Replace the gasket. Gasket must be installed between discharge flange
and casing for proper seal.
Install new discharge flange and thread the four bolts to the casing.
Tighten the bolts in an alternating pattern to avoid pinching
3941-252-00
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6/2016
3941-96, 3942-D6, 3943-96, 3944-96 & 3946-96
Specifications Information and Repair Parts Manual
3-Inch Trash Pump
For Repair Parts contact dealer where pump was purchased.
Please provide following information:
-Model Number
-Serial Number (if any)
Part description and number as shown in parts list
Figure 2 - Repair Parts Illustrations
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3941-96, 3942-D6, 3943-96, 3944-96 & 3946-96
Specifications Information and Repair Parts Manual
Repair Parts List
Ref
No.
Description
Part Number
Qty
Engine 3941-96 B&S 8 HP
1639-024-00
1
Engine 3943-96 Honda 9 HP
1639-026-00
1
Engine 3944-96 Honda 9 HP
1639-028-00
1
Engine 3946-96 B&S 8 HP E-Start
1639-022-00
1
Engine 3942-D6 10 HP Diesel
Discontinued
1
2
Lock Washer
*
4
3
Hex Head Screw
*
4
4
Adapter
2184-001-01
1
5
Wearplate
2182-004-01
1
6
Flat Head Screw, SS
1741-000-00
2
7
O-Ring
Incl. w/ Ref KIT
Seal Assembly - Viton/Silicon Carbide
1640-167-90 & Incl. w/ Ref KIT
1
10
Shaft Sleeve
1555-143-00
1
1
8&9
11
Impeller Shim Package
1656-000-90
1
12
Impeller
3945-012-03
2
13
Hex Head Screw SS
*
1
14
Volute
2184-002-01
1
15
Flapper Valve Assembly
3590-070-90 & Incl. w/ Ref KIT
1
16
Flat Head Screw SS
*
1
17
3” NPT Male Discharge Flange Kit
3941-080-90
1
Fill Plug and O-Ring kit
3SXB-170-90
1
18
3/4” NPT Pipe Plug
*
1
19
Casing
2113-001-00
1
20
Cleanout Gasket
Incl. w/ Ref KIT
1
21
Cleanout Plate
2115-002-01
22
Cleanout Handle
1601-000-00
2
23
Flat Washer
*
2
24
Hex Head Screw
*
4
25
Flat Washer
*
8
26
Raising Block
1990-021-00
2
27
Hex Head Screw and Nut
*
4
28
3” NPT Male Suction Flange Kit
3941-050-90
1
29
3” NPT Suction Strainer
C520-999-90
1
30
(u) Battery Tray Kit Includes:
1696-BAT-K0
1
(includes Ref. No. 16)
(includes Flange, 4 Bolts and Gasket)
17A
(includes Flange, 4 Bolts and Gasket)
12” Battery cable (not shown)
30” Battery Cable (not shown)
31
Roll Cage
1696-100-K0
1
N/S
Replacement Flange Gasket Kit (2 per)
3941-301-90
1
S394-BSC-KO
1
(for Ref. Nos. 17 and 28)
KIT
Complete Seal Kit
(includes Ref. Nos. 7, 8, 9, 10, 15 and 20)
(*)
Standard hardware item, available locally.
(u)
Electric start models only
N/S
Not Shown
Note: Wheel Kit available separately; order model C402-90
3941-252-00
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6/2016
3941-96, 3942-D6, 3943-96, 3944-96 & 3946-96
Specifications Information and Repair Parts Manual
NOTES:
3941-252-00
5
6/2016
3941-96, 3942-D6, 3943-96, 3944-96 & 3946-96
Specifications Information and Repair Parts Manual
NOTES:
3941-252-00
6
6/2016
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